A geotextile is commonly used in subsurface drainage (underdrain) applications. A drain constructed along the edge of a road consisting of a gravel-filled trench wrapped with a drainage geotextile is one example. Other examples include prefabricated geocomposite edge drains, also known as drainboard or dimpleboard and a perforated pipe wrapped with a drainage geotextile sock.
In these systems, the drainage geotextile acts as a filter, allowing the water to pass, while restricting soil fines from entering into, and clogging, the sand, gravel or pipe portion of the drain system.
Woven Slit-Films Not Allowed
Most government agencies and state Department of Transportations have a specification for drainage geotextiles for use as underdrains. In almost all cases, a woven "slit-film" geotextile is not allowed, nor is it recommend for this application.
US Fabrics has a complete line of woven and nonwoven drainage geotextiles. Please click on the links below for a listing of US Fabrics products that meet these specifications and to visit the composite drains, lightweight nonwoven and woven filtration product sections of our website.